In my opinion, Fullscreen FX off and FSAA 4x.

Fullscreen effects apply a bloom that can look nice at times but it ultimately makes the whole image looks like it was smeared in vaseline.
FSAA also helps to mitigate the noise and pixelation generated by how the game renders objects and terrain in the distance.

So in summary, FX off and FSAA to the max. It makes the game look sharp and less noisy.

Full scene FX changes the entire look of the game, and I prefer it. It has some ghosting around the characters which is a bit annoying but overall I definitely prefer the look. Everything is really bright without it.

I have similar debate. I also noticed the Detailed Shadows option is greyed out... anyway. I also forced 16x AF, but doesn't seems worksing.